Best A-Team collaboration

Elton John - mentor, Sir and rocket man - took a moment out of his busy baby-rearing schedule to perform with Ed Sheeran on his hit "The A Team." No stranger to collaborations, Elton is adding Sheeran to his growing Grammy duet list, which includes Eminem and Axl Rose. We're told that for every three Elton bookings the Grammys make, they get one free. Who should join him next year?